The present invention relates generally to the insertion of prewound coils and insulators in magnetic cores such as dynamoelectric machine stator cores. More particularly, the present invention relates to a method and apparatus for placing coils and intermediate insulators in cores in which some coils are already positioned.
A number of machines have been devised for inserting prewound coils as well as, optionally, insulating wedges into stator cores. Illustrative of such machines are the Hill U.S. Pat. No. 3,324,536 and Walker et al., U.S. Pat. No. 3,402,462. Coil placing machines of this type typically include a plurality of generally parallel extending finger elements for supporting coils and a magnetic core into which the coils are to be placed along with a plurality of wedge guides adjacent portions of the finger elements for engaging the magnetic core. A stripper is reciprocable along finger elements to engage and move the coils into the magnetic core and insulating wedge push rods are reciprocable along the wedge guides to engage and force insulating wedges into the core slots radially inwardly of the coils.
While the placement of the insulating wedges which lie radially inwardly of the windings by the same machine which places those windings in the core slots is well established, the machine placement of so called phase insulators which function to separate one winding from another within the dynamoelectric machine stator is for several reasons substantially more difficult to achieve. Typically, such phase insulators will include end turn insulating sheets joined by leg portions intended to lie in the core slots intermediate the windings. Such phase insulators may for example be disposed intermediate the main and start windings of a single phase induction motor or between the several phase windings of a polyphase motor. Pat. illustrating various approaches to the machine insertion of phase insulators include Clark, U.S. Pat. No. 4,090,290; Urick et al., U.S. Pat. No. 4,276,689; and Miller et al., U.S. Pat. No. 4,335,325. These patented schemes have one or more of the following drawbacks: not being readily compatible with coil placing machines of the type illustrated in the above-referenced two patents or with more complex multiple process machines employing such coil placing devices as an integral part thereof; requiring a guide element to be positioned by the operator in the coil placer's tooling; requiring phase insulators having excessive leg length so that the end turn insulating portion of the phase insulator may be separated slightly from the stator at one or both ends thereof; requiring a separate phase insulator inserting step; the occasional tearing of an insulator; the occasional trapping of a portion of the insulator between the coil placing tooling and the stator core; the frequent failure of the leg portion of the phase insulator to adequately separate windings within a slot; and the inadequate reduction in overall dynamoelectric machine stator fabricating time.
Frequently, coil placing machines of the above-referenced type form a part only of a more complex coil winding and placing device as illustrated for example by U.S. Pat. Nos. 3,625,261 and 3,828,830 both to Hill et al. as well as copending U.S. application Ser. No. 294,210, filed Aug. 17, 1981, in the name of Witwer et al. The principles and techniques of the present invention are applicable to a wide variety of coil placing devices of the types referred to above as well as others. Reference may be had to any of the aforementioned patents for details of the machine operation generally.
The copending Witwer and Walker application Ser. No. 429,470 filed Sept. 30, 1982 and entitled "Method and Apparatus For Placing Coils and Intermediate Insulators in Cores" discloses approaches for significantly reducing the above-noted prior art deficiencies. In that application, which is assigned to the assignee of the present invention, a stripper for urging coils axially toward and into a stator core and a further member for urging intermediate insulators into that core commence movement together with the stripper subsequently interrupting its motion to allow the other member to complete placement of the intermediate insulators whereupon the stripper resumes its movement to insert the coils into the core. While this prior system works well in practice, no part of the coil or insulator inserting sequence can commence until the stator core is positioned on the inserter tooling and clamped in place. The time required for placing stator cores in their coil receiving position is dedicated to that task in the sense that commencement of the insertion step must await completion of the stator positioning step. Also, the stator assembling machine parts which effect the temporary interruption of stripper movement during the insertion process add to the overall cost of the stator assembling machine.
Reference may be had to any of the aforementioned patents or patent applications for details of the stator assembling machine and machine operation and the entire disclosures of the two aforementioned Witwer et al. applications are specifically incorporated herein by reference.